Etendue-squeezing illumination optics

ABSTRACT

In some embodiments, an apparatus for use generating illumination is provided that comprises a reflective base, a first light source positioned proximate the reflective base, and a reimaging reflector positioned partially about the first light source, where a percentage of light emitted from the first light source is reflected from the reimaging reflector to the reflective base adjacent the first light source establishing a first real image. The reimaging reflector can further comprise a first sector of a first ellipsoid and a second sector of a second ellipsoid, where the first and second sectors establish the first and a second real image. Further embodiments provide a lens that includes a reimaging reflector that receives light and reflects the light establishing a first real image. The reimaging reflector can further comprise a plurality of sectors that reflect light to establish first and second real images.

PRIORITY CLAIM

This application is a continuation of application Ser. No. 10/772,088,filed Feb. 3, 2004, entitled ETENDUE-SQUEEZING ILLUMINATION OPTICS,which claims the benefit of U.S. Provisional Application No. 60/445,059,file Feb. 4, 2003, entitled ETENDUE-SQUEEZING ILLUMINATION OPTICS, bothof which are incorporated herein by reference in their entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to optical illumination lenses,and more particularly to etendue-squeezing primary source-opticsutilizing either commercially available packaged LEDs or immersive-lensdesigns suitable for LEDs mounted in the chip-on-board fashion.

BACKGROUND OF THE INVENTION

Among the more challenging illumination tasks for solid-state lightingis forward lighting meeting predefined criteria, such as forwardlighting for vehicles, utilizing non-thermal light sources, e.g.light-emitting diodes (LEDs). The lifetime of LEDs in the vibrationenvironment of a ground vehicle is far greater than that of conventionalincandescent sources. Some recently developed white LEDs are surpassingthe significant 100-lumen luminosity threshold, marking the feasibilityof fulfilling that most difficult of all forward vehicle lighting tasks,automotive-headlight intensity standards. Peak intensities in the tensof thousands of candela, however, can not be achieved with LEDs alone.

Beyond efficiency, moreover, automotive design pressures for highlycompact forward-lighting systems pose severe tradeoffs of device sizeagainst attainment of sharp intensity cutoffs required to minimize glareto other vehicles. Prior LED optics employ unacceptable device size whencompared to competing incandescent-source designs such as projectorlamps.

SUMMARY OF THE INVENTION

The above needs are at least partially met through provision of themethod, apparatus, and system for using generating illumination that, insome embodiments, utilize etendue squeezing described in the followingdetailed description, particularly when studied in conjunction with thedrawings. In some embodiments, an apparatus for use generatingillumination is provided that comprises a reflective base, a first lightsource positioned proximate the reflective base, and a reimagingreflector positioned partially about the first light source, where apercentage of light emitted from the first light source is reflectedfrom the reimaging reflector to the reflective base adjacent the firstlight source establishing a first real image of the first light sourceadjacent the first light source such that the reflective base reflectsthe light of the first real image. The reimaging reflector can, in someembodiments, be generally a quarter ellipsoid with a first focuspositioned on the first light source and a second focus positionedproximate the first light source at a position of the first real imageand below the reflective base at a height below a surface of thereflective base equal to a height of a light emitting surface of thefirst light source from the surface. In some embodiments, the reimagingreflector can further comprise a first sector of a first prolateellipsoid and a second sector of a second prolate ellipsoid, where thefirst and second sectors joined along an axis.

Some alternative embodiments provide apparatuses for use in transmittinglight. These apparatuses can comprise a first etendue squeeze lightsource comprising a first reimaging reflector positioned partially aboutthe first light source, where a percentage of light emitted from thefirst light source is reflected from the first reimaging reflectorestablishing a first real image of the first light source adjacent thefirst light source. Some embodiments further include a second etenduesqueeze light source. A luminaire is often included in many embodiments,where the luminaire comprises first and second reflective surfaces,where the first source is positioned proximate an edge of the secondreflective surface to direct light onto the first reflective surface,and the second source is positioned proximate an edge of the firstreflective surface to direct light onto the second reflective surface.The first and second sources can each further include a free-form lenspositioned to receive light from the respective light source and therespective first and second real images, such that the light passesthrough the free-form lens at solid angle subtended by dimensions of thecorresponding first and second reflector surfaces. In some embodiments,a luminaire is included that is generally boat-shaped, with first andsecond reflective surfaces being generally paraboloidal, with the firstsource being positioned at a focal point of the paraboloidal firstsurface and the second source being positioned at a focal point of theparaboloidal second surface.

Further embodiments provide a lens that includes a reimaging reflectorpositioned to receive a percentage of a total light received by thelens. The reimaging reflector reflects the percentage of lightestablishing a first real image that is further directed away from thereimaging reflector and into the lens. The reimaging reflector can begenerally ellipsoidal in shape. Additionally and/or alternatively, thereimaging reflector can further comprise a plurality of sectors whereeach sector is defined by a prolate ellipsoid, such that a first sectorreflects a first sub-percentage of the percentage of light establishingthe first real image, and a second sector reflects a secondsub-percentage of the percentage of light establishing a second realimage that is further directed away from the reimaging reflector andinto the lens. Some lens embodiments further comprises a firstetendue-squeezing reflector and a second etendue-squeezing reflectorboth positioned to receive a percentage of the total light received. Thefirst etendue-squeezing reflector can have a profile comprises aparabola segment and an ellipse segment, where the parabola segment andthe ellipse segment both have a common axis of revolution and meetingwith the same tangent.

Some preferred embodiment provide for a method of manufacturing anoptical device. The method can comprise defining a first position forplacement of an optical source; and defining a first prolateparaboloidal surface further comprising defining a first focus at thefirst position and defining a second focus at a second position a firstdistance from the first position in a first direction, providing athree-dimensional representation of an optical source. The defining ofthe second focus can further include defining a plane relative to theoptical source and the first position such that a second distance isdefined in a second direction from the plane to an emitting surface ofthe optical source, and defining the second focus of the firstparaboloidal surface at a third distance defined in a third directionfrom the plane to the second focus where the third distance is equal tothe second distance such that the third direction is opposite the seconddirection.

Additional embodiments provide methods for manufacturing an opticaldevice. These methods can comprises generating a two-dimensionalrepresentation of a plurality of entry surfaces and a plurality ofcorresponding reflective surfaces, and exit surface; rotationallysweeping the two-dimensional representation about a central axisproviding a three-dimensional representation of the plurality of entryand corresponding reflective surfaces, and exit surface; and defining acutout of the three-dimensional representation that extends from about acenter of the three-dimensional representation at the central axis to aperiphery of the three-dimensional representation providing athree-dimensional representation of an optical lens. Some embodimentsadditionally comprise defining an optical source for positioningproximate the central axis that further comprises: defining a firstposition for placement of an optical source; and defining a firstprolate paraboloidal surface that includes defining a first focus at thefirst position, and defining a second focus at a second position a firstdistance from the first position in a first direction. The defining theoptical source can further comprises defining a second prolateparaboloidal surface by defining a first focus of the second prolateparaboloidal surface at the first position, and defining a second focusof the second prolate paraboloidal surface at a third position a firstdistance from the first position in a second direction opposite thefirst direction.

A better understanding of the features and advantages of the presentinvention will be obtained by reference to the following detaileddescription of the invention and accompanying drawings which set forthan illustrative embodiment in which the principles of the invention areutilized.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentinvention will be more apparent from the following more particulardescription thereof, presented in conjunction with the followingdrawings wherein:

FIG. 1 depicts a simplified elevated view of a circular aperture thatsurrounds a centrally positioned light source;

FIG. 2 shows an elevated view of an aperture having a semicircularconfiguration with an area that is approximately equal to the area ofthe circular aperture of FIG. 1;

FIG. 3 depicts a rectangular aperture that has substantially the samearea as the circular aperture of FIG. 1, but with a length that is aboutfour times the radius of the circular aperture;

FIG. 4 shows a simplified block diagram of a linear array of multipletriangular luminaires with decentered, peripherally positioned, lightsources;

FIG. 5 depicts the configuration of a prolate-ellipsoidal reimagingmirror with central LED;

FIG. 6 depicts the reimaging operation of this mirror;

FIG. 7 depicts a two-sector reimaging mirror;

FIG. 8 depicts is optical operation forming two images;

FIGS. 9 and 10 depict two views of a four-sector reimaging mirror;

FIG. 11 depicts a means of stray-light suppression;

FIG. 12 depicts a right-hand view of reimaging, showing that each sourceimage has 25% of source etendue;

FIG. 13 depicts a left-hand view of reimaging;

FIG. 14 is an outline of a forward-lighting preferred embodiment meetinga low-beam prescription;

FIG. 15 shows a cross section of this preferred embodiment with itsfolded optical path;

FIG. 16 is a perspective rear view of this preferred embodiment;

FIG. 17 is a perspective front view of this preferred embodiment.

FIG. 18 is a cross section of a closely related but thicker preferredembodiment with a fluid-filled interior and one less fold in its path;

FIG. 19 is a perspective view of this preferred embodiment;

FIG. 20 depicts three pairs of low-beam and high-beam versions of thispreferred embodiment, acting in concert with an identical pair tofulfill both prescriptions;

FIG. 21 is a top view of a semicircular lens with a reimaging reflector;

FIG. 22 is a bottom view of this lens, showing how its LED source isreceived;

FIG. 23 depicts an off-axis forward-lighting preferred embodimentmeeting a fog-lamp prescription;

FIG. 24 is an end view of this embodiment, showing its circular symmetryand its linear lens;

FIG. 25 is a lateral view of one lens light-source module, slightly fromabove;

FIG. 26 is a lateral view of the same, slightly from below;

FIG. 27 is a schematic cross-section of the two reflectors depicted inFIGS. 25 and 26;

FIGS. 28-30 depict a decentered circular TIR lens with anetendue-squeezed light source;

FIGS. 31-33 depict a decentered rectangular TIR lens with anetendue-squeezed light source;

FIG. 34 depicts a two-sector boat-shaped luminaire;

FIG. 35 depicts the collimating action of one sector of the luminaire ofFIG. 34;

FIG. 36 shows a faceted version of FIG. 34;

FIG. 37 shows a trisymmetric version of FIG. 34;

FIG. 38 shows a quadrisymmetric version of FIG. 34;

FIG. 39 is the deflection diagram for a source of FIG. 34;

FIG. 40 depicts the deflection diagram similar to that of FIG. 39demonstrating horizontal limit-angles;

FIG. 41 depicts the deflection diagram similar to that of FIGS. 39 and40 showing vertical limit-angles;

FIG. 42 is a cutaway of the source of FIG. 34;

FIG. 43 shows the entire free-form lens of FIG. 42 without cutaway;

FIG. 44 shows a semi-transparent end view of the TIR boat lens withoptical sources similar to the sources depicted in FIGS. 42-43; and

FIG. 45 shows a view from below of a boat lens similar to that of FIG.44 utilizing sections of a circular TIR lens.

Corresponding reference characters indicate corresponding componentsthroughout the several views of the drawings. Skilled artisans willappreciate that elements in the figures are illustrated for simplicityand clarity and have not necessarily been drawn to scale. For example,the dimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help to improve understanding of variousembodiments of the present invention. Also, common but well-understoodelements that are useful or necessary in a commercially feasibleembodiment are typically not depicted in order to facilitate a lessobstructed view of these various embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A better understanding of the features and advantages of the presentembodiments will be obtained by reference to the following detaileddescription of the invention and accompanying drawings, which set forthillustrative examples in the design of which the principles of theembodiments are utilized.

The present embodiments provide for apparatuses and methods for etenduesqueezed light sources, as well as optics and/or luminaries that utilizethe etendue squeezed light sources and are optimized through the use ofthe optics.

Some embodiments provide sources can be utilized to provide forwardvehicle lighting, such as headlights for automobiles that satisfy someof the most challenging forward vehicle-lighting prescriptions. Presentembodiments can further utilize light-emitting diodes (LED) as well assolid-state chip-on-board light sources in general. Moreover, thepreferred embodiments disclosed herein can include configurationscomprising separately molded luminaires and lenses in which thesolid-state chip-on-board light sources are immersed.

The present embodiments relate generally to optical illumination lenses,and some preferred embodiments utilize immersive lens designs suitablefor LEDs mounted in the chip-on-board fashion. Immersion refers to thepractice of surrounding an LED with a transparent dielectric. This canincrease the light-extraction efficiency over the operation of the LEDin air, by decreasing Fresnel reflectance and reducing the extent oftotal internal reflection within the chip. The present embodimentsfurthermore can utilize tailored free-form folded optics to meetparticular prescriptions, such as prescriptions for forward vehicularlighting. The present embodiments can be employed in illumination lensesutilizing a novel optical principle, that of etendue squeezing, forexample through ellipsoidal reimaging as fully described below.

The immersive lens of the LEDs and/or optics utilized with the LEDs canbe formed from substantially any relevant material, such as plastics,polymers, glass, silicon and other such material. Plastic optics can beformed through injection molding of transparent polymeric plastics suchas acrylic, polycarbonate, polyarylate, cyclo-olefins, and other similarmaterials. The cyclo-olefins group, for example, can be used at highoperating temperatures, for example at 161° C., as exemplified by acyclo-olefin based product Zeonor 1600R, produced by Zeon Corporation ofJapan. Optical injection molding is also possible with silicones, whilelow-pressure molding is possible with glass.

The terms used herein of light and illumination are not restricted tothe visible wavelength range of 380 to 750 nanometers, but canadditionally encompass the entire ultraviolet and infrared range that isamenable to geometric optics. In these non-visible ranges, the presentembodiments have similar technological benefits to those it provides inthe visible range. Further, the present embodiments can be equallyapplied to near-ultraviolet LEDs, which may be primary light sources forexciting visible-light phosphors.

In the near-infrared regime (e.g., 700-1100 nm), night-visionilluminators based on the present embodiments can be implemented to usecommercially available near-infrared LEDs as light sources for lensesthat can be molded of the above-mentioned materials, in the same manneras for visible-light illuminators.

Previous LEDs were generally too fragile to withstand the rigors of theinjection-molding process. Recently, however, new chip-on-board designshave eliminated the delicate gold-wire leads that could not withstandinjection molding. Now it becomes possible to precisely mold miniatureoptical elements adjacent to an LED chip. In some embodiments thisability to precisely mold optical elements adjacent to LED chips isutilized.

Government and industry standards for vehicular forward lighting involvea high-intensity hot-spot with a broader and less intense overallpattern that gradually extends sideways but must fall off very rapidlyabove the horizontal plane. In addition, headlights must have high-beamcapability, which requires even higher intensity levels in the hot-spot.Attempts to fulfill such prescriptions through previous LED opticsinvolved configurations that are too thick for injection molding to besuitably produced and/or implemented. Alternatively, the presentembodiments provide luminaire designs with the device size greatlyreduced compared with previous device sizes that were necessary tofulfill forward-lighting prescriptions.

The present embodiments configure and/or arrange light sources toestablish a high-performance etendue light source and/or optics. Aconserved quantity of a bundle of light rays, etendue, is the product ofa bundle area and its projected solid angle. A solid angle, measured insteradians (sr), can be visualized as a piece of the sky, where aprojected solid angle refers to a unit circle below the unit hemisphereon which solid angle is defined.

A solar concentrator makes a small solar image via its concentratedsolar rays converging on its collector from over a much wider angle thanthe half-degree angular width of the Sun as its nearly parallel raysentered the concentrator. Conversely, a searchlight mirror transformsthe omnidirectional emission of a small source into a largewell-directed beam with narrow angular width. Both for concentrators andcollimators, area and angle are traded off, but their product, etendue,generally cannot increase because it is an invariant property of any raybundle, from the moment the bundle was created by the light source. Bygeometric necessity, etendue can only be reduced by removing rays from abundle. The etendue concept can be considered generally analogous to theentropy concept in thermodynamics, where entropy according to the SecondLaw of thermodynamics never decreases.

Etendue is the phase-space volume of a bundle of light rays. If lateralcoordinates x and y are defined across a device aperture Σ, two anglescan be defined according to a light ray passing through these axes.Ray-directions can be defined by variables p and q, defined according tothe cosines of the above two angles, and as multiplied by a localrefractive index n. Thus the dimensions of phase space are x, y, p, andq. Whether a bundle of rays is concentrated or collimated, itsphase-space volume does not change.

The etendue can be determined for substantially any light source. Forexample, if a light source is defined by a square LED chip having anencapsulated dome with an index of refraction n, the etendue of this LEDsource can be given by:E=πn ²(D ²+2DL),  Eq. 1where D is the width and L is the length of the LED. For example, if theLED source has a width D=2 mm, and height L=0.18 mm, and the LED isfurther encapsulated within a spherical dome (such as a dome made of acyclic olefin copolymer) having an index of refraction n=1.53, and theLED is located on a planar mirror so that its side emission radiatesinto a full hemisphere, the etendue equals E=34.71 mm²-sr according toEquation 1.

Similarly, a circular collimator with a nominal diameter (e.g., adiameter of two inches, minus 1 mm for mounting), an optical radius R(for example, a radius R=24.5 mm) and that emits into air can provide anoutput beam, of half-angle θ, that has an etendue defined according to:E=(A _(e))(π sin² θ),  Eq. 2where A_(e)=πR² is the output area. If all of the source rays of theoutput bean exit within the half-angle θ of a system axis, the outputetendue equals the source etendue, and the half-angle can be defined by:

$\begin{matrix}{{\theta = {\sin^{- 1}\sqrt{\frac{E}{\pi^{2}R^{2}}}}},} & {{Eq}.\mspace{14mu} 3}\end{matrix}$so that θ=4.4° is the approximate minimum possible output half-angle,beyond which beam intensity would be generally zero. When luminaireintensity is non-uniform, however, this angle is called the telecentricapproximation, since it often turns out to be close to the angle ofhalf-maximum intensity. As such, the etendue can be defined as a volumein a four-dimensional phase space. The etendue can additionally and/oralternatively be defined according to a two-dimensional phase space witha light source specified by its width D and projected angle, which isgiven by twice the sine of the half-angle θ. The two-dimensional etenduecan be represented as an area on the planar phase space definedaccording to:E_(2d)=2n D sin θ.  Eq. 4

This two dimensional representation of the etendue measure is usefulwhen analyzing rotationally symmetric optics in terms of their diameterand average beam divergence. Commercially available LED chips aretypically squares cut out of a wafer, whereas the rotational symmetry ofa circular chip provides a direct comparison of a full 4-D etendue with2-D etendue. A disc source of width D and height L, embedded in a mediumof refractive index n, emits hemispherically so that θ=90°, giving 2-Detendue according to:E _(2d) =n(2D+2L),  Eq. 5which results in a two dimensional etendue of 6.67 mm (where D=2 mm,L=0.18 mm and n=1.53, as in the example above). The correspondingminimum half-angle is defined according to:

$\begin{matrix}{{\theta_{2\; d} = {\sin^{- 1}\frac{E_{2\; d}}{4\; R}}},} & {{Eq}.\mspace{14mu} 6}\end{matrix}$which equals θ_(2d)=3.90° in continuing the example above where R=24.5mm. The discrepancy with slightly larger value above for a square chipcan be reconciled by considering the four dimensional etendue of arotationally symmetric disc source of diameter D and height L:

$\begin{matrix}{{E = {{\pi\;{n^{2}\left( {\pi\frac{D^{2}}{4}} \right)}} + {\frac{\pi}{2}{n^{2}\left( {\pi\;{DL}} \right)}}}},} & {{Eq}.\mspace{14mu} 7}\end{matrix}$so that the etendue E=27.25 mm²-sr and the four dimensional half-angleθ_(4d)=3.90°.

The output beam of a collimator can be decomposed into elementalbeamlets emitted from small patches of its output surface. The i^(th)beamlet has etendue E_(i), so the total beam has etendue is defined bythe summation:

$\begin{matrix}{E = {\sum\limits_{i}^{\;}{E_{i}.}}} & {{Eq}.\mspace{14mu} 8}\end{matrix}$

One of the important aspects of the present embodiments is the varyingshapes and angular sizes of these beamlets across the output surface ofa luminaire. For example, an edge of a parabolic reflector or mirrorthat is the farthest from a source provides a narrower beamlet than morecentral positions on the reflector closer in proximity to the source. Assuch, the total output beam of a parabola can be defined as a collectionof beamlets of different widths, but all being substantially parallel tothe system axis. In the case of vehicular forward lighting, however, thenarrower beamlets are typically directed so as to promote a rapidvertical cutoff.

Some present embodiments alternatively utilize de-centered collimatorsegments illuminated by etendue-squeezing source optics. The uses ofthese de-centered, etendue-squeezing sources are fully described below.

The United States Department of Transportation (DOT) utilizes alogarithmic definition of intensity gradient (G) at vertical angle θ,according to the intensity values I(θ) and I(θ+0.1°): G=log₁₀ I(θ)−log₁₀I(θ+0.1°). DOT regulation FMVSS 108 mandates G>0.13 for forwardtransmitting vehicular headlights. A gradient according the this mandateresults in an intensity reduction or shrinkage equal to 10^(−0.13)=0.741for every 0.1 degree, a factor of about twenty smaller in only 1° ofelevation. To accomplish this, previous systems require luminaires to bebig enough that its smallest beamlets could be used to meet thisdifficult standard, resulting in excessively large and impracticalluminaries. Alternatively, some present embodiments employ etenduesqueezing allowing for luminaries that are substantially more compactwhile still meeting the regulatory standards and manufacturerpreferences in its prescription.

The present embodiments implement the etendue squeezing through one ofat least two methods, and in some embodiments employ more than onesqueezing method. In some embodiments the etendue squeezing producesnon-circular beamlets with a narrow vertical extent. Such non-circularbundles are directed so as to achieve a high vertical intensitygradient. The thinness of some LED chips, particularly green, blue, andwhite LEDs based on gallium indium nitride, assist this effect throughtheir oblique rays bearing a very thin and elongated chip-image. Someembodiments alternatively and/or additionally implement the etenduesqueezing by shrinking the narrowest beamlets. The shrinking of thenarrowest beamlets is achieved in some embodiments by de-centering alight source.

In previous devices, an omnidirectional light source is typically placedat the center of a luminaire. Alternatively, the present embodimentsposition a light source so that the light source is not centered withrespect to the luminaire and in some embodiments position the lightsource at an edge of a luminaire. De-centering the light sourcelengthens the distance from the light source to the farthest point ofthe aperture, making the narrowest beamlet even narrower than would beachieved in previous devices. This de-centering and/or edge-placementadditionally positions the source closer to the external environment,thereby reducing the thermal paths for removing the source's waste-heat.

Some embodiments additionally redirect portions of the source light tomore completely utilize the source flux. For example, additional opticalmeans are employed near the source so as to redirect what might beunused portions of the omnidirectional emission into the luminaire, asis discussed fully below. When placement of the source is at an edge ofa luminaire, about half of the omnidirectional emission might beredirected and in some instances more than half depending on thepositioning and configuration of the luminaire. In some preferredembodiments employing LED light sources, the dimensions of the opticsemployed in redirecting emissions are maintained to a minimum, forexample, only a few times bigger than the LED source. Further, theredirecting device and/or optics can include a precisely predefinedshape and have precise positioning relative to the source. Someembodiments utilize in-mold-chip-on-board features to implement theredirectional device and/or positioning relative to the source.

In some embodiments, a non-circular aperture is additionally utilized.The aperture can be altered from a circular configuration to accommodatethe peripheral placement of the source and to lengthen the distance fromthe light source to the farthest point of the aperture narrowing thebeamlet. For simplicity, implementation of off-center positioning of asource and/or the aperture re-shaping is hereinafter referred to asetendue squeezing, and is further elucidated below.

A further desired effect and/or desideratum for some lighting, such asvehicular lighting, is a compact configuration. Previous lightingdevices often required long optical path lengths in order to meetexacting prescriptions. These long paths typically resulted inunacceptable device sizes. The present embodiments alternativelyincorporate folded optics to provide increased path lengths whilelimiting the size of the lighting devices.

The present embodiments additionally can be configured to includefreeform optical surfaces specifically configured to shape an outputbeam to both low- and high-beam automobile headlight patterns. As such,the present embodiments can utilize LED light sources to power anynumber of lighting devices, such as automotive headlights. Previousautomotive headlights utilized incandescent sources that have muchhigher power consumption than the LED sources. Additionally, the presentinvention takes advantage of LED's much higher tolerance to vibrationand shock, and much longer lifetimes, which can generally exceed theexpected operating life of automobiles.

FIGS. 1-3 schematically depict simplified elevated views of threeaperture shapes having substantially the same geometric area: a circularaperture 10, a semicircular aperture 13, and a rectangular aperture 16,respectively. Because their areas are substantially equal, the overalletendue of their output beams will typically be the same (assuming asimilar source is employed). It is the narrowest beamlet, however, thatis of interest to the present embodiments. The actual size of thesources shown in these diagrams places them within the purview of thesmall-angle approximation, whereby a small angle and its sine andtangent can be used interchangeably:sin θ˜<θ˜<tan θ.For example, at the ±7.5° of beamlet 12, the sin(θ), θ and tan(θ) inradians equal 0.13053, 0.13090, and 0.13165, respectively, with adifference or an error of +0.6%/−0.3%. The resulting difference or erroris even smaller for beamlets 15 and 18 of FIGS. 2 and 3, respectively.Further, the difference or error does not reach ±1% until the angle ofthe beamlet is about θ=14°.

FIG. 1 depicts a simplified elevated view of a circular aperture 10 thatsurrounds a centrally positioned light source 11. A beamlet 12 isdefined by a pair of rays that span the distance from source 11 to theperiphery of the aperture 10. The ratio of the radius of source 11 tothat of the radius of the aperture 10 defines an angular semi-width ofthe beamlet 12 that is the narrowest beamlet from the luminaire. It isnoted that for the sake of simplicity, FIGS. 1-3 do not show beamlets12, 15, and 18 being redirected out of the plane of the paper, thedirection of emission from the apertures 10, 13, and 16, respectively.

FIG. 2 shows an elevated view of an aperture 13 having a semicircularconfiguration with an area that is approximately equal to the area ofthe circular aperture 10 of FIG. 1. The distance from the source 14 tothe periphery of the semicircular aperture 13, however, is about√{square root over (2)} times greater than the distance 12 from thesource 11 to the periphery of the circular aperture 10 of FIG. 1. Thebeamlet 15 is accordingly about √{square root over (2)} times narrowerin angle than the beamlet 12 of circular aperture 10 of FIG. 1.

Referring to FIG. 3, a rectangular aperture 16 is shown that hassubstantially the same area as circular aperture 10 of FIG. 1, but thelength of the aperture 16 is about four times the radius of the circularaperture 10. The beamlet 18 is thus also about four times smaller inangular width than beamlet 12.

The de-centering of a light source relative to an aperture lengthens thedistance from the light source to the farthest point of the aperture andprovides for the reduced beamlet angular width. The reduced angularwidth provided by the off center positioning of the source allows, inpart for the promotion of a rapid vertical cutoff. Additionally, thenarrowed beamlet angular width can provide for a high vertical intensitygradient.

FIG. 4 depicts an array 1000 of equilateral generally triangular-shapedluminaires 1001, each with lensed light source 1002, whichadvantageously lie on an edge of the luminaries. By positioning thesources 1002 on an edge of the array, the tasks of conveying electricpower to and removing waste heat from the sources are simplified.

Some preferred embodiments utilize edge-placement tactics and/oradditionally redirect omnidirectional source-emissions to be redirectedinto a narrower solid angle subtended by an aperture from the source, toin part avoid wasting luminous flux. In utilizing a semi-circularaperture such as the aperture of FIG. 2, for example, the presentembodiments redirect substantially all, and preferably all of the fluxthat would have been direction in a −Y direction to instead beredirected in the +Y direction and thereby into semicircular aperture13.

This redirection can be achieved in some embodiments through theutilization of a mirror. For example, a vertically oriented planarmirror could be used, but such a flat mirror would preferably bepositioned immediately adjacent to the source 14, to avoid a dark gapthat might appear between the source and its adjacent image. Ahemispheric mirror positioned to be centered on the source could beemployed with sources that allowed free passage of those reflected raysavoiding dark gaps, and LEDs typically do not allow free passage ofreflected rays.

In one preferred embodiment of the present invention, the redirection oflight from the source can be implemented through an ellipsoid reflector,with non-imaging achieved by designing and position the ellipsoid withits focus at an edge of the source. The edge-ray principle ofnon-imaging optics utilized in the present embodiments advantageouslystrive to ensure that substantially all, and preferably all reflectedsource-rays appear to come from an image immediately adjacent to thesource, even though a surface of an ellipsoid reflector itself isdistant from the source.

FIG. 5 depicts a simplified schematic view of a portion of a prolateellipsoid reflector 20, an LED chip 21, a substrate 22, and a cutawayview of a mirror or reflective base 23. The LED 21 and ellipsoidreflector 20 are positioned relative to each other such that a firstfocus F1 of the ellipsoid is positioned on the surface of chip 21, at apoint (F1X,F1Y,F1Z) that is in some preferred embodiments on the edge ofthe LED, and a second focus F2 is positioned at a point (F2X,F2Y,F2Z).In some preferred embodiments, the ellipsoid reflector is configuredand/or positioned relative to the source such that the second focus F2is positioned to be below the mirror 23, and laterally displaced fromthe first focus F1 by a width W of the LED chip 21. The real image canbe positioned such that a small safety gap or guard-distance Δ can beincluded between the source and an adjacent real image of the source,which can be any sized gap, for example about 0.05 mm in someembodiments, depending on the size of the source, ellipsoid reflector,and other similar factors.

The surface of ellipsoidal mirror 20 can further be configured accordingto some design considerations to pass through a point P at (PX,PY,PZ).The size of ellipsoidal mirror 20 is relative to the size of the source21 in achieving accurate reimaging. An ellipsoid center 24 lies midwaybetween the first and second foci F1 and F2, with a center-to-focusdistance c given byc=½√[(F1X−F2X)²+(F1Y−F2Y)²+(F1Z−F2Z)²].

The location of surface point P fulfills the definition of an ellipse asthe locus of points of constant sum 2a of the distances from it to eachfocus, where a is the semi-major axis, accordingly given by:

$a = {\frac{1}{2}{\left( \sqrt{\begin{matrix}{\left\lbrack {\left( {{PX} - {F\; 1\; X}} \right)^{2} + \left( {{PY} - {F\; 1\; Y}} \right)^{2} + \left( {{PZ} - {F\; 1\; Z}} \right)^{2}} \right\rbrack +} \\\left\lbrack {\left( {{PX} - {F\; 2\; X}} \right)^{2} + \left( {{PY} - {F\; 2\; Y}} \right)^{2} + \left( {{PZ} - {F\; 2\; Z}} \right)^{2}} \right\rbrack\end{matrix}} \right).}}$A Semi-minor axis b is given by b=√{square root over ((a²−c²)},completing the specification of the ellipsoid by the coordinates of thefoci and of a single point on its surface. Prolate ellipsoid 20 isdelineated by polar grid 25, which is aligned with axis defined by aline joining foci F1 and F2.

Still referring to FIG. 5, the ellipsoid is configured such that thesecond focus F2 is defined to have a depth below the mirror 23 that istwice the height at which the first focus F1 above the mirror. This isso that the real image of the chip, as formed by ellipsoid 20, is atsame height as the chip itself. In some embodiments, the second focus F2can also be shifted slightly further away from the LED chip 21 so thatthere is a small gap between the chip and its real image, in an attemptto avoid reflected rays from hit the chip.

Similar etendue squeezing can be achieved with other shaped sources suchas rectangular, oval and substantially any other shape with the sourceoff center and appropriate reflectance to generate reimaging and achievethe desired illumination pattern. As described above with reference toFIG. 3, a source can be rectangular with the LED positioned off center.

FIG. 6 depicts the reimaging action of prolate ellipsoidal reflector 20on a percentage of emission 26 from chip 21. A real image 27 is formedon mirror 23, adjacent to chip 21, of the percentage of the lightemitted from the light source 21 that impinges the reimaging reflector20. The real image 27 thereafter acts as a virtual source equivalent toanother chip at that location. The percentage of rays striking reflector20 would have otherwise continued outward, but are now recruited intoimage 27. A difficulty arises in some implementations, however, as shownby rays 26 b, which can be seen to intercept chip 21 on their way toimage 27. Some present embodiments alleviate this problem by utilizing atwo-sector ellipsoid reflector.

FIG. 7 depicts a simplified elevated view of a two-sector reimagingmirror 30 according to some embodiments. Reimaging mirror 30 includes afirst or left-half prolate ellipsoid 30L and second or right-halfprolate ellipsoid 30R, each configured similarly in specification and insome embodiments substantially identical in specification, to ellipsoid20 of FIG. 2 and FIG. 2A. Right-half prolate ellipsoid is centered atpoint 30Rc, while left-half prolate ellipsoid 30L has a correspondingcenter point, not shown, on the other side of source 31. The two sectorsabut and are joined along centerline 30CL and share defining point 30P.LED chip 31, substrate 32, and mirror or reflective base 33 are similarto those described above in relation to FIG. 2.

FIG. 8 depicts the reimaging action of two-sector ellipsoidal reflector30 of FIG. 3. LED chip 31 produces emission and a percentage of theemissions 36 are directed toward the reimaging reflector 30. Asub-percentage of the emissions are reimaged by right-side reimagingreflector or mirror 30R providing a right-side real image 37R andanother sub-percentage of the emissions are reimaged by left-sidereimaging mirror 37L providing a left-side real image 37L. In utilizingthe two ellipsoid halves 30R and 30L, the present embodiments solve theproblem of rays impacting the source as described above in relation toFIG. 2A. It can also be seen that right-side image 37R radiates into thefront-right quadrant of directions. Thus images 37R, and 37L equally,each bear approximately 25% of the etendue of light source 31, as isfully discussed below, for example with respect to FIG. 11 below.However, the amount reflected by the ellipsoidal reflector depends onthe size of the ellipsoidal and the placement of the source relative tothe ellipsoidal.

FIGS. 9-10 depict simplified schematic diagrams of a four-sectorreimaging mirror 40 according to some present embodiments. Four-sectorreimaging mirror 40 includes upper sectors 40RU and 40LU, and lowersectors 40RL and 40LL. Each of the four sectors meet or are joined alonga center line. The four sectors 40RU, 40RL, 40LU and 40LL are configuredsuch that the reflected rays do not impinge on the chip and rather arereflected so as to clear the height of chip slug 42, which can beemployed to remove waste heat from high-power LED chip 41 and conveys itto a reflective base such as a mirrored circuit board 43. Upperellipsoids 40RU and 40LU form real images defined below the mirror, suchthat the images reflected from the mirror 43 appear to come from thesame height as source 41. Lower ellipsoids 40RL and 40LL, however, havetheir second focus at the same height as the first focus, on the edge ofthe chip, forming a real image.

In some embodiments, reimaging mirrors such as those depicted in FIG. 7and FIG. 10 can be filled with a transparent dielectric. When configuredas stand-alone packages, the dielectric can be epoxy or a similarlyprotective transparent encapsulated.

The reimaging mirrors of the present invention can be integrated withother preferred embodiments. The stand alone packages have to be bondedor otherwise secured to these devices. The bonding of the mirrors can bea laborious process that can introduce positional errors and thepossibility of degrading or debilitating air bubbles. Alternatively, insome embodiments the present invention utilizes injection-moldablechip-on-board LEDs. The present invention takes advantage of their greatpositional accuracy of chip placement. The reimaging mirrors disclosedabove become part of the external surfaces of the optical devices of thepresent invention. This allows an entire optical device to be completedin each brief molding cycle. Thereafter, the portions comprising thereimaging mirrors can be masked off and vacuum-metalized incost-effectively large batches.

Referring back to FIG. 8, reimaging reflector 30 forms real images 37Land 37R to either side of light-source 31. FIG. 11 depicts a planar viewof a reflective base such as a metalized surface 51, as well as LED chip50, and two reflective images 50L and 50R isolated for clarity. LED chip50 lies at the center of metalized surface 51. A reimaging reflector(not shown), such as a two-sector re-imaging reflector 30 (see FIG. 7),has formed images 50L and 50R on either side of chip 50, spacedlaterally therefrom with a small 5% gap. Surface 51 includes specularmirror strip 52 extending to either side of chip 50, and blackenedsections 53 covering portions of mirror 51 or the remainder of themirror. Specular mirror strip 52 reflects the real images 50L and 50Rback to form virtual sources. Blackened sections 52 act to suppressstray light. This implementation of the present invention achieves arapid peripheral cutoff of light intensity. Such a cutoff is animportant aspect of vehicle forward lighting, the prescriptions forwhich contain challenging requirements for rapid cutoffs of intensity.

The concept of etendue squeezing is elucidated in FIG. 12, depicting aright-lateral slant view of surface 51 comprising mirror strip 52 anddarkened zones 53. LED chip 50 shines into an entire hemisphere ofdirections. A two-sector reimaging mirror, such as the reimaging mirror30 in FIG. 7 but not shown, intercepts the rear semi-hemisphere ofray-directions and reimages them. The remaining front semi-hemisphere ofdirections proceed outward directly from chip 50, constitutingapproximately 50% of the original etendue. Right image 50R is formed bythe left sector 30L of reimaging mirror 30 of FIG. 7, and thus shinesinto the right front quadrant of viewing directions, constituting 25% ofthe original etendue.

FIG. 12 is the corresponding left-lateral slant view of surface 51. LEDchip 50 is directly visible from these directions as well. Right image50R shines to the right, so left image 50L is visible instead,constituting the 25% of etendue reimaged by the right sector 30R ofreimaging mirror 30 of FIG. 7.

As such, some preferred embodiments utilize the off-center positioningof the source relative to an aperture and/or the redirecting of aportion of the illuminance from the source to achieve the desiredetendue squeezing. The etendue squeezing can further be utilized toprovide a light source with increased light extraction efficiency andthus improved output.

Referring back to FIG. 2, semicircular aperture 13 is an example of aluminaire shape that benefits from the reimaging just described above,which generates a virtual source with emission matching the semicircle.Disclosed below are preferred embodiments exemplifying implementationsfor reimaging reflectors to be utilized in beam-forming luminaries,including monolithic verses stand-alone configurations.

In monolithic preferred embodiments, a relatively large luminaire isformed. Typically, the luminaire is formed through injection-molding,but it can be formed through other methods. The luminaire includes animmersed chip-on-board LED source and adjacent reimaging reflectorformed by a metalized portion of its exterior, and further surfaces thatutilize a folded optical path and tailored surfaces that produce thedesired output pattern.

FIG. 14 depicts a cross-section of monolithic injection-moldedLED-activated forward-lighting lens 60. Lens 60 includes a cavity 61 forbonding to an LED light source of matching shape, reimaging mirror 62(which can have a configuration similar to that of mirror 40 of FIG. 9and FIG. 9), reflective surface 63, optically inactive surface 64,free-form profile 65 of fluted cylindrical reflector array 66, opticallyinactive surface 67, mirrored slightly cylindrical surface 68, andcylindrical output surface 69.

FIG. 15 depicts a cross-sectional view of the lens 60 of FIG. 14 showingthe folded-optics path according to one embodiment of the presentinvention. Light source 60 s emits ray-fan 260. The source ray fan isreflected into rays 261, which are in turn reflected by surfaces 63 and65 into rays 262, which propagate to cylindrical surface 69. Thereuponthey are internally reflected into rays 263, which proceed to mirror ormetalized reflective surface 68, which reflects them into rays 264.These rays finally pass through exit surface 69, which can in someembodiments refractively shape them into parallel output rays 265. Thisray-trace is schematic in that original ray-fan 260 represents only onepoint on source 60 s. The full ray trace from all points of source 60 sproduces the far-field intensity pattern that can be configured tofulfill a low-beam forward-lighting prescription for vehicle lighting,but such a fully populated ray-set would be too dense to illustrate thefolded-optic principle depicted in FIG. 15.

Referring to FIGS. 14 and 15, a Low-Beam version of the lens assembly 60can comprise six LED sources 60 s and associated cylindrical optics. TheHigh-Beam version can include four LED sources and associated opticsbecause the High-Beam version typically acts in concert with theLow-Beam lens to fulfill the high-beam prescription. In some particularimplementations, three high- and low-beam pairs of preferred embodimentsdepicted in FIG. 14 are contemplated to be deployed on both the driverand passenger sides of a vehicle.

In some implementations of the lens 60 of FIG. 14, the cylindrical exitsurface 69 can be specified for Low-Beam by the profile:

$x = {{- 2983.834126} + {300.534153\sqrt{1 - \left( \frac{z - 6030 + 036}{2227.350635} \right)^{2}}}}$where: 21.2009 ≤ z ≤ 103.4.The Low-Beam version of slightly cylindrical-surface profile 68 of FIG.14 can be calculated according to some embodiments by the equation:

$x = {\sum\limits_{i = 0}^{40}{a_{i}{z^{i}.}}}$In accordance with the x and z axes shown in FIG. 14. In one embodiment,for example, with the z-coordinates ranging between54.1465<z<104.257199, the following forty, exponentially-enumeratedcoefficients can apply:

a0 = −2.21460914986206E+03 a15 = −5.14375335063617E−25 a29 =−2.65183970375481E−53 a1 = 2.75318242799951E+02 a16 =2.07456025635039E−27 a30 = 1.97105582858789E−56 a2 =−1.39140271474280E+01 a17 = 4.43885292165034E−29 a31 =9.89655644255562E−58 a3 = 3.42598288270074E−01 a18 =8.75965292053517E−32 a32 = −6.86592593163378E−60 a4 =−3.44847449501444E−03 a19 = 2.98020397200867E−35 a33 =1.60672475580861E−61 a5 = −1.35476338668418E−05 a20 =−3.22552137227001E−35 a34 = −9.71287078142620E−65 a6 =4.44982939515977E−07 a21 = −1.23028112571408E−37 a35 =−4.49245295716173E−66 a7 = 2.13776164953985E−09 a22 =1.81445438824544E−39 a36 = −1.53060029633236E−68 a8 =−8.00681271717953E−11 a23 = 4.39029354997865E−42 a37 =−1.07731162863745E−69 a9 = 3.00505167111001E−13 a24 =−2.48776544540972E−43 a38 = 9.33508280183508E−72 a10 =3.49966331738797E−16 a25 = 1.87261011855604E−45 a39 =2.94808304533197E−74 a11 = 4.47644506312821E−18 a26 =2.15314083102648E−47 a40 = −2.75183781043199E−76 a12 =2.99425509845293E−19 a27 = −1.25136131545428E−49 a13 =−6.94530535532736E−22 a28 = 7.09194506048832E−52 a14 =−1.86789647810197E−23 a15 = −5.14375335063617E−25In FIG. 6, exit surface 69 can be specified for High-Beam by:

$x = {{- 2983.534112}\; + {3004.534182\sqrt{1 - \left( \frac{z - 60.0 + 0.6}{2227.350657} \right)^{2}}}}$where: 21.2009 ≤ z ≤ 103.4.The High-Beam version of surface provide 68 of FIG. 14 can be calculatedby:

$x = {\sum\limits_{i = 0}^{20}\;{a_{i}{z^{i}.}}}$As a further example, with the z-coordinates in the range 56.3934<z,103.505155, the following twenty exponentially-enumerated coefficientscan apply:

a0 = 1.86745049546039E+02 a1 = −2.45183532823518E+00 a2 =−8.83374361022387E−01 a3 = 4.83677655754712E−02 a4 =−1.06746203638527E−03 a5 = 1.06458096224462E−05 a6 =−2.80679144614359E−08 a7 = −1.24917819162495E−10 a8 =−2.27028758125753E−12 a9 = 3.73212124311632E−14 a10 =−2.83214999584491E−16 a11 = 2.42909307529820E−18 a12 =9.67052619279627E−21 a13 = −1.99999922061327E−22 a14 =−2.71940787015645E−24 a15 = 4.46695148016903E−26 a16 =−1.54285041259005E−28 a17 = −9.05950796672694E−31 a18 =1.76303842155717E−32 a19 = −1.30807575155329E−34 a20 =3.59238240211839E−37

FIG. 16 is a perspective view of monolithic injection-molded lens 60according to one embodiment of the present invention, which is similarto the lens shown in FIGS. 14 and 15. Lens 60 includes integral mountingbrackets 60B, reimaging reflectors 62, metalized reflectors 63, flutedslightly cylindrical reflectors 66, optically inactive surface 67, andreflective surface 68.

FIG. 17 is an isometric view of monolithic injection-molded lens 60depicting the integral mounting brackets 60B, LED-receiving cavities 61,optically inactive surface 64, and slightly cylindrical output surface69.

FIG. 18 is a perspective view of a bank 70 of monolithic injectionmolded lenses 60 that can be implemented for example with vehicleheadlights, two of which can at least fulfill forward-lightingprescriptions. The bank 70 depicted in FIG. 18 comprises three low-beamluminaires 60, each having, for example, six light sources such as theLEDs 60 s depicted in FIG. 16, and three matching High-Beam preferredembodiments 60H, each having, for example, four LEDs 60 s as shown. Abank 70 of monolithic injection molded lenses however can include anynumber of luminaries depending on the desired implementation.

FIG. 19 and FIG. 20 depict a similar preferred embodiment forsolid-state forward lighting, but with one less reflective path-foldthan in FIG. 14. Monolithic injection molded lens 600 compriseshemispheric input surface 601, reimaging ellipsoid 602, reflectivefree-form cylindrical fingers 603, inactive planar face 604,reflectively coated planar folding face 605, planar exit face 606,inactive top face 608, and mounting tabs 609. Input surface 601 receivesLED 610. Interior cavity 607 is utilized to mold such a thick part, andafter molding is filled with an index-matching fluid.

As an example of the semicircular configuration 13 of FIG. 2,semicircular luminaire 700 is depicted in FIGS. 21-22. Top view FIG. 21shows luminaire 700 comprising four-sector reimaging reflector 701,semicircular RXI lens 702 formed by top surface 702 t and reflectivebottom surface 702 b, and central refractive semi-lens 703.

Bottom view FIG. 22 shows luminaire 700 further comprising free-formair-gap cavity 704 for shaping source output, semi-hemispheric cavity705 for adhesion to a transparent LED dome, shelf 706, sidewall 707, andbase 708.

A preferred embodiment fulfilling a vehicular fog lamp prescription isdepicted in FIG. 23. Forward lighting system 80 comprises linearaspheric beam-shaping lens 81 and multiple lensed LEDs 82. Schematiccoordinate axes 80 c show lamp orientation is on a slanted frontsurface, indicating the off-axis capability of this preferredembodiment.

FIG. 24 is an end view depicting aspheric linear lens 81, comprisingouter surface 81U and inner surface 81L, intercepting the 60° ray-fanbetween left edge ray intercepting light between upper edge ray 82U andlower edge ray 82L, and lensed primary optic 82, comprising outeraxially symmetric surface 821, outer semi-hemispheric surface 822, andinterior surface of reimaging ellipsoid 823. LED dome 801 is positionedconcentric with 821 and 822. Dividing line 82L functionally bisects the120° arc of surface 821, demarcating the below-mentioned upper and lowerinterior reflectors, which respectively illuminate lower and upperhalves of linear lens 81.

The totality of luminous effects of this multiplicity ofetendue-squeezing preferred embodiments is the fulfillment of a fog-lampprescription into a direction off the surface normal of the localvehicle surface.

FIG. 25 and FIG. 26 are lateral views of primary optic 82, comprisingouter surfaces 821 and 822, reimaging ellipsoid 823 focused at chipwithin dome 801 of LED package 800, lower etendue-squeezing reflector824, and upper etendue-squeezing reflector 825 with associated30°-tilted upper planar mirror 826.

FIG. 27 shows a schematic profile illustrating the operational geometryof etendue-squeezing mirrors 824 and 825, which are surfaces ofrevolution of this profile, which comprises an ellipse cotangent to aconfocal parabola. Profile 850 comprises parabola segment 850 p andellipse segment 850 e, both with common axis of revolution 853 andmeeting with the same tangent. First focus 851 is on the light-emittingchip, coincident with the primary focus of reimaging ellipsoid 823 ofFIG. 26. Ellipse section 850 e reimages the chip at second focus 852, onplanar mirror 827 or 828. First focus 851 is also the focus of parabolicsection 850 p, which has inclined axis 855.

The linear lens 81 of FIG. 24 can, according to some implementations, bespecified on its upper surface 81U by:

${z = {\sum\limits_{i = 0}^{n}{a_{n} \cdot y}}},$which can be defined according to the following forty enumeratedcoefficients.

a₀ 23.7323461896680357 a₁ −2.35756210296816437 a₂ 1.62726704588258642 a₃−0.716661159390062252 a₄ 0.230627519895498456 a₅ −0.0564977755152250571a₆ 0.0101731514516384385 a₇ −0.00123530871192474557 a₈  8.22806412403507132e−05 a₉  8.2636979882550525e−08 a₁₀ −5.1692174132151874e−07 a₁₁   4.34660979003263823e−08 a₁₂−1.94731619467607768e−09 a₁₃   1.04274639743941907e−10 a₁₄−7.67061191589676232e−12 a₁₅   3.60046020675626574e−13 a₁₆−9.75636966897008181e−15 a₁₇   2.57329992290836079e−16 a₁₈−1.17974640217786435e−17 a₁₉   8.74556046777561242e−19 a₂₀−5.42971511106852066e−20 a₂₁   4.81286126939681239e−21 a₂₂−3.44029477543583054e−22 a₂₃   1.66258036297390458e−24 a₂₄  1.35676812793622248e−25 a₂₅   6.17139635634764269e−26 a₂₆−2.99632515535625432e−27 a₂₇   2.56147058170827249e−29 a₂₈−4.21504548477108204e−30 a₂₉   2.78590988668004316e−31 a₃₀−2.99571633535578293e−33 a₃₁   2.68809672210511845e−34 a₃₂−3.85311166574406139e−35 a₃₃   9.68114003166518218e−37 a₃₄ −4.638252512241093e−38 a₃₅   9.37651641899118408e−39 a₃₆−2.92030037424059245e−40 a₃₇ −1.17243288653282526e−41 a₃₈  3.60867110660494119e−43 a₃₉   1.51578486617199042e−44 a₄₀−4.46533565034798503e−46The lower surface 81L can be defined according to one implementation by:

${z = {\sum\limits_{i = 0}^{n}{b_{n} \cdot y}}},$which can be defined according to the following forty enumeratedcoefficients.

b₀ 19.6299091524472828 b₁ −1.57277089370702794 b₂ 0.554983044885405619b₃ −0.240472306798358959 b₄ 0.0737927033665797261 b₅−0.0152046436738344417 b₆ 0.00196793313140879037 b₇−0.000132060182759310458 b₈ −1.98011048767264361e−07   b₉6.62443944313761817e−07 b₁₀ −2.46249819372499411e−08   b₁₁−2.11842097765186506e−09   b₁₂ 1.70083704559306457e−10 b₁₃−2.41773961950242511e−12   b₁₄ 7.60192304332669464e−14 b₁₅−8.3619247479718772e−15 b₁₆ −1.12275996810063414e−16   b₁₇−1.70125051352445508e−17   b₁₈ 7.55096542652264318e−19 b₁₉1.72224335764688652e−19 b₂₀  3.3869990475210065e−21 b₂₁−8.76634599954845472e−22   b₂₂ 2.67590881265907127e−24 b₂₃−7.04240087666460112e−25   b₂₄  1.3825053029168974e−25 b₂₅−2.04243983423132075e−27   b₂₆ −2.3917673643133041e−28 b₂₇2.41616030487243679e−29 b₂₈ 2.24389533033019912e−31 b₂₉−5.36319627700966982e−32   b₃₀ −2.26856806324107915e−33   b₃₁−1.17597262150234576e−34   b₃₂ 1.76818189483146931e−36 b₃₃1.09431265893002939e−36 b₃₄ 1.53367733581741235e−38 b₃₅9.50032297431148229e−40 b₃₆ −2.99988743265351054e−40   b₃₇2.91117469243712755e−42 b₃₈ −1.27191927772221192e−43   b₃₉ 3.6206737915041727e−44 b₄₀ −9.68629343022934038e−46  

In stand-alone preferred embodiments, a smaller injection-moldedconfiguration surrounds the chip-on-board LED source, comprising areimaging reflector and a free-form surface shaped to produce awide-angle pattern tailored for injection through the intervening air orother medium to an adjacent beam-forming luminaire. Preferredembodiments employ decentered installation of their light sources, inthe manner depicted in FIGS. 2-4. An etendue-squeezing reflector isemployed to redirect source-light into the solid angle subtended by theluminaire.

FIGS. 28, 29, and 30 show a side view, an elevation view from below anda lateral view from below, respectively, of decentered circular totallyinternally reflecting (TIR) lens 90 and stand-alone light source 95. TIRlens 90 is formed from a complete circular TIR lens as a cutoutgenerally circular section half the original diameter, with one edge atthe circle's center and the other at its periphery. Decentered lens 90includes central refractive lens 90 c, grooved facets 91 with entryfaces 92 to receive light and totally internally reflecting faces 93 toredirect upwards to exit through circular top face 94. Light source 95comprises metalized reimaging reflector 96 which can be similar toreimaging reflectors of FIGS. 3-4, tailored free-form exit face 97, andbase 98 configured to produce an etendue-squeezed output beam that isdirected towards the TIR lens 90.

FIG. 31, FIG. 32, and FIG. 33 show different views of decentered,generally rectangular TIR lens 100 and stand-alone light source 105according to one embodiment of the present invention. The rectangularshape is useful in many different applications, for example in vehicularstyling of lamps meeting prescription for fog lamps. TIR lens 100 can beformed in some embodiments according to a complete circular TIR lens andconfiguration as a rectangular section of length with dimensions thatextend from center to edge of the circular TIR lens configuration.Decentered rectangular lens 100 includes central refractive lens 100 c,grooved facets 101 with entry faces 102 to receive light and totallyinternally reflecting faces 103 to redirect upwards to exit throughrectangular top face 104. Light source 105 includes metalized reimagingreflector 106, tailored free-form exit face 107, and base 108.

FIGS. 34 and 35 depict simplified schematic diagrams of a luminaire orreflector 110 according to one embodiment that utilizes light sources113 and 114 that employ etendue squeezing. Generally boat-shapedluminaire 110 includes a first or left-half paraboloidal reflector 111,a second or right-half paraboloidal reflector 112, a first light source113, which illuminates the surface of right-half reflector 112 from aposition about its focal point, and light source 114, which illuminatesthe surface of reflector 111 from a position about the focal point ofreflector 111.

In previous devices, a conventional circular paraboloidal mirror with acentral source has the disadvantage in that the central portions of thereflector are positioned quite close to the light source and thereforetend to produce beamlets much wider than most of the beam, wastefullyproducing a probably useless dim fringe extending around the main beam.

Alternatively in one preferred embodiment of boat-shaped luminaire 110,light sources 113 and 114 are positioned at a distance or removed fromtheir corresponding reflectors (112 and 111, respectively) and thussubstantially avoid producing such wasteful wide-angle beamlets. Somepresent embodiments utilize light sources 113 and 114 that employetendue squeezing. The etendue squeezing, as described above, limits thedirection of emitted light from each source towards its correspondingreflector. Such an arrangement avoids the production of wasted lightbeing emitted from the sources in directions away from the reflectors111, 112. This etendue squeezing is illustrated in FIG. 35, depictingexamples of some rays 115 emitted by the first source 113 and redirectedby the corresponding first reflector 111 into a beam 116, which in someembodiments can be a collimated beam.

High flux-utilization includes the efficient optical coupling of anLED-chip's hemispheric emission to the paraboloidal sector focused uponit. For a beam meeting forward-lighting prescriptions and particularlytheir rapid vertical cutoffs, etendue squeezing enables overall devicesize to be minimized, by giving up rapid horizontal cutoffs. Thus acombination of reimaging reflector and free-form tailored lens sends theappropriate local-intensity pattern for input to its paraboloidal-sectorreflector. This squeezing is illustrated in FIG. 35, depicting rays 115emitted by source-luminaire 113 and thence redirected by reflector 111into elongated collimated beam 116.

Additional degrees of optical-design freedom are available whenutilizing sources with etendue squeezed output to satisfy thecomplexities of a forward-lighting prescription. FIG. 36 depicts aslanted side view into the interior of boat-shaped reflector 120 withfacets 121, which deviate in small amounts from the paraboloidal shapeof FIGS. 34 and 35 in order to reshape its narrow collimated beam intoone meeting a forward-lighting prescription. Source luminaires 122 and123 illuminate their corresponding reflective sectors 124 and 125,respectively. Bottom seam or fold-line 126 is darkened for emphasis.

FIG. 37 depicts a preferred embodiment with triangular symmetry.Luminaire 130 comprises paraboloidal-reflector segment 131 r andcorresponding source 131 s, segments 132 r and 133 r and correspondingsources 132 s and 133 s. Preferred embodiments with an odd-fold symmetrywould have their sources located on the intersections of reflectorsegments.

FIG. 38 depicts preferred embodiment 1300 with quadrilateral symmetry.Source 1301 s illuminates opposing paraboloidal segment 1301 r, and thesame for sources 1302 s, 1303 s, and 1304 s and reflector segments 1302r, 1303 r, and 1304 r, respectively. These reflector segments could bespecialized in various horizontal and vertical aspects of meeting aforward-lighting prescription. Preferred embodiments with an even-foldsymmetry would have their sources at the middle of opposing reflectorsegments.

The light sources indicated in FIG. 36 and FIGS. 37-38 have free-formlensing appropriate to the solid angle subtended by their correspondingreflector segments. In order to understand this free-form geometry, FIG.39 is a deflection diagram depicting the solid angle subtended byparaboloidal sector 140 as seen from source 140 s (see FIG. 41),analogous to the reflector sectors of FIGS. 34-35. Source-view FIG. 39shows the position of centroid 140 c of the solid angle subtended byreflector sector 140. Its angular semi-dimensions of 60° horizontal and18° vertical are respectively established in top view FIG. 40 byhorizontal edge rays 140 eh and in FIG. 41 by vertical edge rays 140 ev.FIG. 40 shows that horizontal edge rays 140 eh involve an inward 30°deflection of the ±90° limiting rays coming from a virtual sourcesimilar to that formed in FIG. 8. This 30° deflection can be done by asingle refraction. Lateral view FIG. 41 shows that the ±18° verticaledge rays 140 ev are within 27° of the ±45° vertical limits of a virtualsource similar to that formed in FIG. 8, so that the entire deflectiondiagram of FIG. 39 can be accomplished refractively, as will be shownnext.

FIGS. 42 and 43 depict views of luminaire 150 comprising LED chip 151,mirrored base 152, two-sector reimaging reflector 153, and free-formrefractive lens 154 in cutaway in FIG. 42. Lens 154 compresses theluminous output of the virtual source, formed by reflector 153, into thesolid angle of FIG. 39.

The principal difference between a paraboloidal versus a TIR-lensdeployment is that the TIR lens version utilizes the upright orientationshown in FIGS. 39-41, while the reflector has an upside-down attitude,shining down into its reflector segment.

FIG. 44 is an end view of luminaire 160 comprising boat-shaped TIR lens161 with upper exit surface 161 e and conical lateral surface 161 s, andcorrespondingly confocal lensed light sources 162 s and 163 s, eachdedicated to its respective oppositely situated TIR lens-slice 162 t and163 t. Light sources 162 s and 163 s correspond to details of FIGS.42-43, respectively comprising central LED chips 162 c and 163 c,reimaging reflectors 162 r and 163 r, and free-form lenses 162L and163L.

FIG. 45 is a perspective view from below of TIR lens slices 162 t and163 t, and correspondingly confocal lensed light sources 162 s and 163s, cutaway to reveal LED chips 162 c and 163 c. Reimaging reflectors 162r and 163 r are configured to face outward and away from correspondingTIR lens 162 t and 163 t.

In the embodiment depicted in FIGS. 44 and 45, the sources 162 s, 163 sare positioned below the TIR lenses 162 t and 163 t, respectively. Thisblow-lens, out-of-beam position of the source of a TIR-lens collimatorallows the source to be positioned so that the source does not block thebeam. Thus, in a TIR boat lens the sources can be positioned somewhatinside the lens periphery, rather than fixed on the periphery as theywould in the reflector versions discussed above. This positioned allowseach source 162 s, 163 s to have an unblocked view of its correspondingTIR-lens collimator, 162 t, 163 t.

In some preferred embodiments, the facet number of the TIR lens areoptimized in relation to the location of its cutting plane so that thecentral portions of luminaire 160 have illuminated facets. The moldsections for the injection molding of this preferred embodiment couldadvantageously be sections of a single circularly symmetric moldconventionally fabricated by rotating machinery. In these preferredembodiments, the TIR boat-lens advantageously has both light sourcessituated from their corresponding TIR-lens slices 162 t, 163 t, that theresultant exit beams have a narrow range of beamlet sizes. The freeformlens configuration of the sources 162 s, 163 s, shown in FIGS. 42-43 canbe shaped for use with the TIR lens 161 so as to direct illuminationover the TIR lens slices 162 t, 163 t to give good uniformity ofilluminance at exit-surface 161 e of boat-shaped TIR lens 161.

The present embodiments employ novel design principles and combinationsof those design principles. One aspect of some present embodimentsutilizes in-mold placement of chip-on-board light emitting diodes (LED)within an injection-molded immersive optical device. Another aspect ofsome of the present embodiments provides an enhanced optical source byetendue squeezing, a novel optical principle disclosed herein.Additionally, some preferred embodiments utilizes multi-sectorellipsoidal reimaging mirrors as a particular means of implementingetendue-squeezing. The present invention additionally employs compactfolded-optic configurations utilizing tailored free-form surfaces tomeet particular output prescriptions, particularly low-beam andhigh-beam automotive forward lighting.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention set forth in the claims.

1. An apparatus for use in generating illumination, comprising: a first light source; a generally planar reflective base positioned adjacent to and extending away from the first light source; and a reimaging reflector positioned separated from the first light source and partially surrounding the first light source, where the reimaging reflector extends from the generally planar reflective base to partially reflectively surround the first light source, where a first percentage of light is emitted from the first light source in a first solid angle and does not strike the reimaging reflector, and a second remaining percentage of light emitted from the first light source is reflected from the reimaging reflector to the generally planar reflective base and is further reflected from the generally planar reflective base to be directed into substantially a same solid angle as the first solid angle of the first percentage of light emitted from the first light source thereby achieving etendue squeezing of the first light source.
 2. The apparatus of claim 1, wherein the second percentage of light is approximately half of the light emitted from the first light source, where the reimaging reflector reflects at least a portion of the second percentage of light to the reflective base adjacent the first light source, where the portion of the second percentage reflected to the reflective base defines a first real image of the first light source adjacent the first light source such that the reflective base reflects the light of the first real image into substantially the first solid angle.
 3. The apparatus of claim 2, wherein that the first light source and the adjacent first real image define a virtual light source thereby reducing a solid angle of light emissions without substantially increasing etendue of the first light source.
 4. The apparatus of claim 3, wherein the reimaging reflector is generally a quarter ellipsoid with a first focus positioned on the first light source and a second focus positioned proximate the first light source at a position of the first real image adjacent the first light source such that the second focus is further positioned at a distance below the reflective base approximately equal to twice a height of a light emitting surface of the first light source from a reflective surface of the reflective base.
 5. The apparatus of claim 1, wherein the reimaging reflector is approximately quarter-spherical and comprises a first reflective surface defined by a first sector of a first prolate ellipsoid and a second reflective surface defined by a second sector of a second prolate ellipsoid, where the first and second reflective surfaces are adjacent and joined along a first axis aligned with the first light source, where a first portion of the second percentage of the light reflected from the reimaging reflector is reflected from the first reflective surface to the reflective base adjacent the first light source defining a first real image of the first light source adjacent the first light source on a first side of the first light source such that the reflective base reflects the light of the first real image into substantially the first solid angle, and a second portion of the second percentage of the light reflected from the reimaging reflector is reflected from the second reflective surface to the reflective base adjacent the first light source establishing a second real image of the first light source adjacent the first light source at a second side of the first light source opposite the first side of the first light source and separated from the first real image by the first light source, such that the reflective base reflects the light of the second real image into substantially the first solid angle.
 6. The apparatus of claim 5, wherein the first and second real images are aligned with the first light source along a second axis that is about perpendicular to the first axis such that the aligned first light source, the first real image and the second real image define a virtual source having a surface area that is at least twice a surface area of the first light source.
 7. The apparatus of claim 5, wherein the first reflective surface of the reimaging reflector is defined by the first ellipsoid having first and second foci, and the second reflective surface of the reimaging reflector is defined by the second ellipsoid having third and fourth foci; the first reflective surface is positioned relative to the first light source such that the first focus is positioned on the first light source and the second focus is positioned to the first side of the first light source proximate the first light source at a position of the first real image; and the second reflective surface is positioned such that the third focus is positioned on the first light source and the fourth focus is positioned to the second side of the first light source proximate the first light source at a position of the second real image.
 8. The apparatus of claim 1, wherein the reimaging reflector comprises four sectors distributed along an axis aligned with the first light source where each of the four sectors are defined by one of four prolate ellipsoids, where a first portion of light reflected from the reimaging reflector is reflected by first and second sectors of the reimaging reflector to the reflective base at a first side of the first light source establishing a first real image of the first light source, and where a second remaining portion of light reflected from the reimaging reflector is reflected by third and fourth sectors of the reimaging reflector to the reflective base adjacent the first light source on a second side of the first light source establishing a second real image of the first light source adjacent the first light source, such that the reflective base reflects the light of the first and second real images.
 9. The apparatus of claim 1, further comprising: a tailored free-form exit face positioned such that the first percentage of light emitted into the first solid angle from the first light source and the second percentage of light reflected by the reimaging reflector and reflective base is emitted from the exit face establishing an output illumination that meets a predefined prescription.
 10. The apparatus of claim 1, further comprising: an optical system wherein the first light source is positioned proximate the optical system such that the optical system receives the light at substantially the first solid angle as emitted from the first light source and reflected from the reimaging reflector and the reflective base.
 11. The apparatus of claim 10, wherein the optical system comprises the reimaging reflector, and a cavity in which the first light source is positioned.
 12. The apparatus of claim 11, wherein the lens further comprises: first reflective surface positioned to receive the light at substantially the first solid angle as emitted from the first light source and reflected from the reimaging reflector and the reflective base; a reflector array positioned to receive and reflect light reflected from the first reflective surface; a mirrored surface positioned to receive and reflect reflected light from the reflector array; and an output surface through which the light reflected by the mirrored surface is emitted.
 13. The apparatus of claim 10, wherein the optical system comprises a collimator that directs the light received at substantially the first solid angle as emitted from the first light source and reflected from the reimaging reflector and the reflective base into a collimated output beam.
 14. The apparatus of claim 13, wherein the collimator comprises a totally internally reflecting (TIR) lens positioned proximate the first light source opposite from the reimaging reflector such that the TIR lens receives the light at substantially the first solid angle as emitted from the first light source and reflected from the reimaging reflector and the reflective base.
 15. The apparatus of claim 14, wherein the TIR lens is a decentered lens comprising an exit face, a central refractive lens, grooved facets having entry faces to receive the light, and totally internally reflecting faces positioned relative to the grooved entry faces to receive the light entering the lens from the entry faces of the grooved facets and to reflect the received light to the exit face.
 16. The apparatus of claim 14, wherein the TIR lens comprises a decentered generally rectangular TIR lens having dimensions of a rectangular section of length defined according to a defining complete circular TIR lens extend from a center to a peripheral edge of the defining complete circular TIR lens.
 17. The apparatus of claim 13, wherein the collimator comprises a semicircular refractive, reflexive and internal reflection (RXI) lens positioned adjacent the light source to receive the light at substantially the first solid angle as emitted from the first light source and reflected from the reimaging reflector and the reflective base, and to emit the collimated beam.
 18. The apparatus of claim 10, further comprising: a first additional reimaging reflector, a second additional reimaging reflector and at least an additional planar reflective surface, where the first additional reimagining reflector is positioned relative to the first light source to receive at least a first portion of the light emitted from the first light source at substantially the first solid angle and reflects the first portion of light to the additional planar reflective surface to be reflected into a second solid angle, the second additional reimagining reflector is positioned relative to the first light source to receive at least a second portion of the light emitted from the first light source at substantially the first solid angle and reflects at least a fraction of the second portion of light to the additional planar reflective surface to be reflected into the second solid angle.
 19. The apparatus of claim 18, wherein the first and second additional reimaging reflectors comprise an ellipse cotangent to a confocal parabola with the second additionally reimaging reflector positioned about the first additional reimaging reflector.
 20. The apparatus of claim 18, wherein the first and second additional reimaging reflectors comprise reflective surfaces comprising an ellipse segment cotangent to a confocal parabola segment with the confocal parabola segment and the ellipse segment both having a common axis of revolution and meeting with a same tangent.
 21. The apparatus of claim 1, further comprising: a first luminaire comprising the a first light source, the generally planar reflective base and the reimaging reflector; a second luminaire comprising: a second light source; an additional generally planar reflective base positioned adjacent to and extending away from the second light source; and an additional reimaging reflector positioned separated from the second light source and partially surrounding the second light source, where the reimaging reflector extending from the generally planar reflective base to partially reflectively surround the second light source, where a first percentage of light is emitted from the second light source in a third solid angle and does not strike the additional reimaging reflector, and a second remaining percentage of light emitted from the second light source is reflected from the reimaging reflector to the additional generally planar reflective base and is further reflected from the additional generally planar reflective base to be directed into substantially a same solid angle as the third solid angle of the first percentage of light emitted from the second light source thereby achieving etendue squeezing of the second light source.
 22. An apparatus for use in generating an illumination, comprising: a first off-center etendue squeeze imaged light source; and an optical system optically coupled with the first off-center light source such that the optical system receives the light emitted from the first off-center light source; wherein the first off-center light source comprises: a first reflective base; a first light source positioned on the first reflective base; and a first generally quarter spherical reimaging reflector optically aligned with the first light source, extending from the first reflective base and partially surrounding the first light source, where the first light source emits a first percentage of light such that it does not strike the first reimaging reflector and directs a second percentage of light at the first reimaging reflection, wherein the first reimaging reflector comprises a generally ellipsoidal reflective surface opposed to the first light source to reflect at least a portion of the second percentage of light emitted from the first light source to the first reflective base defining a first real image of the first light source adjacent the first light source, where the first reflective base reflects the light of the first real image away from the first reimaging reflector generally in alignment with the first percentage of light emitted from the first light source.
 23. The apparatus of claim 22, further comprising: a second off-center etendue squeeze imaged light source optically coupled with the optical system such that the optical system received the light emitted from the second off-center light source; wherein the second off-center light source comprises: a second reflective base; a second light source positioned on the second reflective base; and a second generally quarter spherical reimaging reflector optically aligned with the second light source, extending from the second reflective base and partially surrounding the second light source, where the second light source emits a first percentage of light such that the first percentage of light emitted from the second source does not strike the second reimaging reflector and directs a second percentage of light at the second reimaging reflection, wherein the second reimaging reflector comprises a generally ellipsoidal reflective surface opposed to the second light source to reflect at least a portion of the second percentage of light emitted from the second light source to the second reflective base defining a first real image of the second light source adjacent the second light source, where the second reflective base reflects the light of the first real image of the second light source away from the second reimaging reflector generally in alignment with the first percentage of light emitted from the second light source.
 24. The apparatus of claim 23, wherein the optical system comprises a totally internally reflecting (TIR) lens positioned proximate the first and second off-center light sources such that the TIR lens receives the first percentage of light from the first and second light sources and the light of the first real images of the first and second light sources reflected by the first and second reflective bases, respectively.
 25. The apparatus of claim 24, wherein the TIR lens comprises an exit face, grooved facets having entry faces to receive the light, and totally internally reflecting faces positioned relative to the grooved entry faces to receive the light entering the lens from the entry faces of the grooved facets and to reflect the received light to the exit face.
 26. The apparatus of claim 22, wherein the optical system comprises a semicircular refractive, reflexive and internal reflection (RXI) lens positioned adjacent the light source to receive the first percentage of light from the first light source and the light of the first real image of the first light source reflected by the first reflective base, and to emit a collimated beam.
 27. The apparatus of claim 22, wherein the first off-center light source comprises a second reimaging reflector, a third reimaging reflector and a second planar reflective surface, where the second reimagining reflector is positioned relative to the first light source to receive at least a first portion of the light emitted from the first light source and reflects the first portion of light to the second planar reflective surface such that the second planar reflective surface reflects the first portion of light, the third reimagining reflector is positioned relative to the first light source to receive at least a second portion of the light emitted from the first light source and reflects at least a fraction of the second portion of light to the second planar reflective surface such that the second planar reflective surface reflects the fraction of the second portion of light.
 28. The apparatus of claim 27, wherein the second and third reimaging reflectors comprise an ellipse cotangent to a confocal parabola with the third reimaging reflector positioned about the second reimaging reflector.
 29. The apparatus of claim 27, wherein the second and third reimaging reflectors comprise reflective surfaces comprising an ellipse segment cotangent to a confocal parabola segment with the confocal parabola segment and the ellipse segment both having a common axis of revolution and meeting with a same tangent. 